timofurrer / tag-expressions

Python implementation of Shunting-yard Algorithm to evaluate logical tag expressions

tag-expressions

Package to evaluate logical tag expressions by using a modified version of the Shunting Yard algorithm. This package is a Python port of cucumbers tag expression.

It's also used by radish.

Installing

$ pip install tag-expressions

Here is a tease

>>> from tagexpressions import parse
>>>
>>> expression = '( a and b ) or ( c and d )'
>>> compiled_expression = parse(expression)
>>> print(compiled_expression)
( ( a and b ) or ( c and d ) )
>>>
>>> data = ['a', 'b', 'c', 'd']
>>> assert compiled_expression.evaluate(data) == True
>>>
>>> data = ['a', 'c']
>>> assert compiled_expression.evaluate(data) == False
>>>
>>>
>>> expression = 'not a or b and not c or not d or e and f'
>>> compiled_expression = parse(expression)
>>> print(compiled_expression)
( ( ( not ( a ) or ( b and not ( c ) ) ) or not ( d ) ) or ( e and f ) )
>>>
>>> data = ['b', 'e', 'f']
>>> assert compiled_expression.evaluate(data) == True
>>>
>>> data = ['a', 'c', 'd']
>>> assert compiled_expression.evaluate(data) == False

Usage

Available operators

• or - "or" conjunction of two given variables
• and - "and" conjunction of two given variables
• not - negation of a single variable

Every other token given in an infix is considered a variable.

Operator precedence

From high to low:

• ()
• or
• and
• not

tag-expressions's Issues

Credentials posted in .travis.yml

tag-expressions/.travis.yml

Lines 26 to 28 in 9b58c34

	user: tuxtimo
	password:
	secure: 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